The projects' overall objectives are (a) to study the molecular biology of human cytomegalovirus (CMV), including viral gene replication, gene regulation, genomic structure, strain variation and the virus-cell interaction that might bear upon the mechanism of viral latency and the possible basis of herpes viral oncogenesis; (b) to elucidate the mode of viral transmission in interuterine infection and to (c) understand the biopathology of CMV infection. These objectives will be accomplished by the following approaches: a) constructing a CMV DNA fragment map using various restriction endonucleases and various nucleic acid hybridization techniques; b) detection of the specific site of viral gene replication and transcription by high resolution EM; characterization of the bipartite and oblate chromatin in CMV infected cell by various biochemical and biophysical techniques; c) the assignment of the function of various DNA fragment by nucleic acid hybridization in vitro translation; d) continuing the effort in establishment of genetic relatedness between CMV and other herpes group viruses by nucleic acid hybridization and restriction enzyme analysis; e) the study of the mode of virus transmission, strain variation and viral strain relatedness by restriction endonuclease analysis; f) continuing the effort in location of viral genome, viral antigen, and susceptible cell type by nucleic acid hybridization and various immunological techniques. These approaches should provide the necessary information for understanding of the phenomena of viral latency and virus pathogenesis.